Average Return Calculator
Calculate arithmetic mean, CAGR, volatility and more from annual returns.
Calculate the arithmetic mean, geometric mean (CAGR), volatility, and best/worst years from a series of annual investment returns.
How Average Return Calculator Works
The arithmetic mean simply averages the annual percentage returns you enter. The geometric mean — better known as CAGR (Compound Annual Growth Rate) — instead multiplies together (1 + each year's return), takes the nth root, and subtracts 1, which correctly accounts for the compounding effect of gains and losses on each other. The geometric mean is always lower than the arithmetic mean whenever returns vary from year to year, because volatility drags down compounded results.
Standard deviation measures how far individual yearly returns typically stray from the average, giving a volatility reading: under 10% is classified as low volatility, 10–20% as moderate, and above 20% as high — useful shorthand for how bumpy the ride was to earn that average return.
Total return over the full period is calculated by compounding all the individual annual returns together, which is the actual cumulative growth an investor would have experienced, separate from any single year's average.
See It In Action
Who Uses Average Return Calculator and Why
- Summarizing several years of an investment\'s annual returns into a single average figure for comparison purposes.
- Getting the more accurate compounded (CAGR) figure instead of a misleading simple average when judging real long-term performance.
- Checking how volatile a return series has been using the standard deviation and best/worst year figures.
- Comparing the cumulative total return of a multi-year holding against its average annual return.
Mistakes to Avoid
- Using the arithmetic mean as if it were the compounded return you actually experienced — the arithmetic mean overstates real performance whenever returns vary year to year, since it doesn\'t account for how losses and gains interact multiplicatively.
- Assuming a 50% loss followed by a 50% gain nets out to breakeven — it doesn\'t; a 50% loss followed by a 50% gain leaves you down 25% overall, which is exactly the kind of distortion the geometric mean (CAGR) corrects for and the arithmetic mean hides.
- Judging risk from the average return alone — two investments can share the same average return with very different standard deviations, meaning very different year-to-year volatility.
Tips for Best Results
- Use CAGR, not the arithmetic mean, whenever you want to know what an investment actually returned over the full period — it\'s the number that reflects real compounding.
- Pay attention to the standard deviation figure alongside the average — a similar average return with a much higher standard deviation means a bumpier, higher-risk ride to get there.
Fixing Common Problems
My CAGR came out noticeably lower than my arithmetic mean. — This is expected whenever returns vary from year to year — the more volatile the return series, the larger the gap between the arithmetic mean and the geometric mean (CAGR), since compounding penalizes volatility.
Terms Explained
Geometric mean (CAGR): The compound annual growth rate — the single annualized return that, applied consistently, would produce the same cumulative result as the actual year-by-year returns.
Standard deviation: A measure of how much individual yearly returns typically stray from the average, used here as a volatility gauge.